Generally, walking aids may be used in any instance where an individual's ability to ambulate normally has been impaired or decreased. Many people, including the elderly, use a walking aid. Such users often consist of patients suffering from injuries or other disabilities that affect their lower extremities, including the legs and feet. For example, in the instance where an individual has suffered a leg injury, therapy is often required to retrain the person to walk properly. Patients with various disabilities, such as those who have suffered from a stroke, amputations, deconditioning, and Parkinson's disease, often have difficulty walking following the onset of illness and must use a walker or other walking aid. Similarly, many patients with fractured lower extremities and other injuries require the use of walking aids during their recovery phase. Numerous types of walking aids of varied designs are available and utilized for the treatment of these and many other pathological conditions. Examples of such devices may be found in U.S. Pat. Nos. 3,517,677, 5,020,560, 5,167,597, and 5,172,715.
During these instances, and in many cases permanently, a walking aid is required to assist the patient to walk safely. In order to ensure maximum freedom and safety, and track the user's physical condition and progress in using the walking aid, it is necessary to evaluate the user's gait both qualitatively and quantitatively. Therefore, in order to aid patients with disabilities in the rehabilitation process and to allow them to stand and walk in a stable manner, it is necessary to be able to monitor their dynamic gait performance and correct any deficiencies detected. Also, measurement of the user's performance with the walking aid is necessary to assure that patients remain stable not just while walking but also when reaching for objects, transitioning from standing to sitting positions, and in other situations encountered in daily life. It is also important to know the weight distribution between the individual and the walking aid to determine if the user is leaning too far backwards and therefore might fall.
In addition, patients with lower extremities fractures are commonly instructed by their physicians to use a walking aid and bear only a certain percentage of their weight on the fractured lower extremity. Too much weight can cause further injury and too little weight can slow the healing process. A typical current practice calls for instructing the patient to stand on two scales, one beneath each leg, and learn to shift his/her body weight to reduce the load on the injured leg to within the prescribed range. However, this static teaching technique does not work well when the patient begins to walk and cannot sense the weight distribution.
There is thus a need to monitor a person's dynamic gait while using a walking aid. This is commonly done by having a therapist assist the user of the walking aid and monitor his/her performance. This method, however, provides for only limited qualitative analysis and no quantitative analysis of a person's gait.
Several gait measurement techniques of limited utility are known. For example, devices have been developed to determine the dynamic loads exerted on patients using crutches at the crutch handles and axilla as described in Wilson, et. al. The device uses force plate type transducers and other stationary sensor systems to indirectly measure the forces. However, this system is not capable of measuring dynamic gait performance. In addition, load cells have been used to study the forces exerted on a crutch, but this approach has many drawbacks. The crutch must be cut apart in order to place the cell in the crutch which alters the construction of the crutch. In addition, load cells can only measure either axial or bending forces, but not both simultaneously. Furthermore, an appropriate load cell for this application is too heavy to mount in the crutch because it will alter the crutch's characteristics by changing the weight and balance.
None of the known devices and techniques are capable of adequately measuring the dynamic gait performance of the user/patient. One problem is that there is no reliable way to measure the stability of a person using a walking aid. Often while a patient may successfully use a walking aid during normal ambulation, a fall may occur while reaching for an item on a shelf or opening a door. The standard method for the evaluation of an individual using a patient aid is by subjective observation by a physician or therapist (clinician). Stability determinations, however, require quantitative measurements, which obviously cannot be determined in this manner.
There is thus a need for walking aids that provide biofeedback to the patient in order to assist the patient in proper use of the device.
There is further need for walking aids that can be interfaced to an electronic or computer system to quantitatively define the deficiencies in ambulation and gait.
There is a further need to track patient progress through defined parameters such as stability and the percentage of body weight borne by the walker so as to insure proper rehabilitation and recovery.